Motors and Power Units
The general design for these power units is the same but it seems to take me a long time to work out the details. My concern is mostly about the aesthetics of the units and has relatively little to do with function.
It begins with a search through my scrap box of old motors. I pull out all the stepper motors; mostly salvaged from scrapped printers and disk drives. The results are bigger than I'd like (again with the aesthetics). So I search the internet.
For about $11.00 I can buy a set of 5 stepper motors; complete with driver boards: ( FTCBlock 5 Sets 28BYJ-48 ULN2003 5V Stepper Motor ULN2003 Driver Board with 40pin Jumper Wire for Arduino ) I'm not sure if these small motors will have enough torque but for it's worth a try.
This first power unit I built for the 'large' clock (shown below) made a lot of noise when running at clock speed. It had a direct drive to the drive gear so the motor had to run too slowly. Each step made a distinct click and this was a little anoying. So I made a second unit with a gear reduction to speed up the motor. This resulted in less clicking (less vibration) and therefore a quieter operation.
These new motors have a 1/64 reduction built-in so that should take care of the noise issues. We'll see...
